1. Field of the Invention
The present invention relates to communication systems, and more particularly, to a dual-standby terminal having a plurality of low-noise amplifiers and a method for operating wireless communication units thereof.
2. Description of the Related Art
In recent years, portable terminals have been developed to provide a variety of functions, such as a message transmission, a video call, an electronic note, an Internet function, etc., as well as a voice call. A dual-standby terminal is now available to provide a simultaneous call function with two or more wireless communication networks simultaneously. The dual-standby terminals can perform a simultaneous call connection between heterogeneous wireless networks as well as homogeneous wireless networks. For example, a dual-standby terminal can establish a simultaneous call between heterogeneous wireless networks (for example, CDMA-GSM networks) as well as homogeneous wireless networks (for example, GSM-GSM networks). To this end, the dual-standby terminal includes a plurality of wireless communication units.
If a dual-standby terminal with a plurality of wireless communication units performs a simultaneous call, the plurality of wireless communication units is activated. In that case, the transmission power of a first wireless communication unit may affect the reception path of a second wireless communication unit. As a result, the transmission power of the first wireless communication unit may cause the low-noise amplifier (LNA) of the second wireless communication unit to be saturated or oscillated, thereby deteriorating the reception performance of the second wireless communication unit. Moreover, since the transmission power of the first wireless communication unit increases relatively in a weak electrical field area, it may further deteriorate the reception performance of the second wireless communication unit. To resolve this problem, a plurality of low noise amplifiers may be serially connected to each other along the reception path of the wireless communication unit. However, this type of configuration causes increased power consumption in a battery. Therefore, there is a need for a system to enhance the call quality when a dual-standby terminal performs a simultaneous call connection and reduce power consumption of the battery.